Delisting Animal’s from the Endangered Species List
By: Hayden Wolfe
The Endangered Species Act of 1973 was enacted to conserve the ecosystems of endangered animals (Congress 1973). An endangered species is one, which throughout a portion of its range, is in danger of extinction (Congress 1973). Recovery plans and removal from the the list are an objective of the Endangered Species Act (Congress 1973). However, there is often disagreement on when the time is appropriate to remove species from this list. Some organizations are against removing animals like Ursus arctos (grizzly bears) from the list at this time (Sierra 2015). I put forth that U. arctos should be removed from the endangered species list.
Some groups argue that U. arctos should not be delisted. They argue that the survival rate of U. arctos has flattened, and cubs have a lower survival rate (Sierra 2015). They also argue that the bears’ population is isolated from others (Sierra 2015). They point out that the supply of Pinus albicaulis (whitebark pine), a food source of U. arctos, is being depleted (Sierra 2015).
U. arctos cub survival is strongly correlated with population density, and density dependent factors tend to have a greater affect near carrying capacity (Manen 2016). Therefore, the drop in cub survival and the leveling out of the overall survival rate indicate that this population has reached its carrying capacity.
This also seems to discount P. albicaulis as the cause of the change in the survival rate, as increased U. arctos density is seen to be the actual culprit (Manen 2016). Carrying capacity is the population that can be sustained by the landscape into the foreseeable future (Cain 2011). Last March, I was at an informal presentation by the Interagency Grizzly Bear Study Team, they proposed that the species be delisted. They argued that the animal’s had reached carrying capacity and that while they are still isolated from other populations in Canada they have exceeded Franklin’s Number a common metric used to measure minimum viable population.
The Endangered Species Act is intended to recover species that are in danger of extinction (Congress 1973).
Although there are some reasonable concerns regarding the delisting of U. arctos they do not have a foundation strong enough to prevent the Endangered Species Act from fulfilling its purpose. U. arctos should be removed from the Endangered Species List.
Cited References
108th Congress (US). 1973. Endangered Species Act of 1973. Washington D.C.: Department of the Interior (US).
Cain ML, Bowman WD, and Hacker SD. 2011. Ecology. Sunderland (MA): Sinauer Associates, Inc. 214 p.
Manen FT, Haroldson MA, Bjornlie DD, Thomson DJ, Costello CM, and White GC. 2016. Density Dependence, Whitebark Pine, and Vital Rates of Grizzly Bears. The Journal of Wildlife Management. 80(2): 300-313.
Sierra Club. 2015. Grizzly Bear Recovery & Endangered Species Act Protection [Internet]. [Cited 16 September 2016]. Available from
https://www.sierraclub.org/sites/www.sierraclub.org/files/uploads-wysiwig/Grizzly%20Bear%20Recovery%20and%20Endangered%20Species%20Act%20Protection%20Fact%20Sheet_0.pdf
Kathy
Interesting argument. I had no idea.